Zenith 24-T-2 backfire

[Lowbarn]

Do I need to advance or retard the ignition to try easing backfires through the carburettor?

The issue has been gradually getting more prevalent recently.

This carburettor has always backfired occasionally when the engines warming up. 
The feul side has been fully cleaned out and is now properly filtered. That did help for a while, not only with the backfire but also smoother running.

I have not replaced anything in the distributor in two years running. Only cleaned the points couple times. I don’t do as many miles as I should!

Any advice gratefully accepted as always. 
Richard.

[jpsmit]

In my experience backfiring in the top of the engine is usually the engine running lean. Backfiring in the exhaust is the engine running rich. Check your plugs - there are all kinds of comparison photos on the interwebnet but generally lean plugs look white (I think like cigarette ash colour)

[Lowbarn]

Good point.
I haven’t fiddled with the mixture setting, l’m always wary of making things worse!
Could be a blocked jet even though I cleaned it all out.

I am planning to get a carb rebuild kit when I can find the time to figure out which parts I need.

[Austin in the Shed]

It could depend on whether the zenith is jetted correctly for a 7 .In the 50’s they produced a replacement carb for the worn out 7 ones numbered 1372 I think,that also has the correct flange pattern for an updraft manifold.
The 24t2 was fitted to lots of engines from single cylinders to fergie tractors .